Oregon State will take the first step today towards turning the page to the 2013 season when they begin spring practice in Corvallis. The Oregon State defense enjoyed a solid season in 2012. Will they achieve the same success this upcoming season? Here are the top five storylines for the Beavers' defense heading into spring practice:

1. Search for the next Jordan Poyer: Replacing an All-American is never easy, particularly a ballhawking safety that posted the numbers Poyer did in 2012: 51 tackles, seven interceptions, seven pass breakups. Not to mention the leadership and guidance he gave to Oregon State's younger players. His all-around skills are why Poyer should go in the early rounds of the NFL Draft next month.

"How do you replace a guy like Poyer that's made so many plays?" Mike Riley asked rhetorically during a recent teleconference. "We have to find that corner than can start and develop good backups. We have a lot of names, but nobody has the job or there is anybody we feel great about backing up until we see them play in the spring and fall camp."

So, who's next in line? Likely, one of two players will earn the right to succeed Poyer - rising senior Sean Martin or acclaimed junior college transfer Steven Nelson, rated by Rivals.com as one of the top JUCO defensive backs prospects in the country for the 2013 recruiting cycle.

While it hasn't benefitted from the notoriety given the high-profile quarterback battle, the tussle between Martin and Nelson for the starting cornerback spot should become one of the highlights of the spring.

Martin was the third cornerback a season ago behind Poyer and Rashaad Reynolds, who returns for his final season as a Beaver. Martin had 43 tackles, two interceptions and three pass breakups.

"We feel good about the growth of Sean Martin. He's a great kid, a hard worker and conscientious," Riley said. "We anticipate him being at his highest level so far. Knock on wood, he finally shook the injury bug that held him back for so long. He couldn't stay healthy, so he couldn't really develop. He got more opportunities to play last year and that was all good for him. We'll see if he can step up into what could be a reliable starting role."

Riley sought somebody to come in and compete immediately with Martin, and Nelson, a one-time Georgia commitment, appears to be the perfect choice. Nelson de-committed from Georgia in November and eventually signed with the Beavers after visiting to Corvallis.

"We recruit junior college players to hopefully impact the competition immediately and we think Steven Nelson is a prime example of that," Riley said. "He is a very talented guy and he has a gym rat attitude. He's always around and working out. He has fit in with our team in a short period of time. I anticipate good things from him in spring ball. The best thing that can happen to this team is develop a really good competition between good players at corner."

2. Finding a new force in the middle: Since outside linebackers Michael Doctor and D.J. Alexander both return, the lone concern for defensive coordinator Mark Banker is finding someone to take over for Feti Unga, who was sixth on the team with 56 tackles and started 19 games in his career. The lack of experience by the potential replacements, a list that includes Jabral Johnson, Joel Skotte, Caleb Saulo worries Riley.

"We need to find a middle linebacker," Riley said. "We have about four names there, but none of them have played much. So, we're looking for development there."

In addition to finding a middle linebacker, Riley desires to build depth behind Doctor and Alexander.

"We need some linebackers to step forward," Riley said. "We feel good about the outside linebackers. Alexander and Doctor can take another next step up. They played a lot of good football last year. So, their improvement is important. So is finding guys that can play with them. They have to step up. They have a lot of work to do and a lot of development to occur before they're ready for prime time."

3. Reloading at defensive tackle: The departures of the dependable Castro Masaniai and Andrew Seumalo to graduation, along with reserve tackle Joe Lopez (awarded a scholarship at Portland State), means Oregon State must rebuild the interior of the defensive front. Junior college transfers Edwin Delva and Siale Hautau will be on campus for the spring semester and participate in spring practice, giving them a head start.

"Delva and Hautau should immediately provide us with some good competition there," Riley said. "They are junior college players we expect to be competitive right away. When you look at that group, we have some veteran players there like Mona Rosa and Brandon Bennett-Jackson. But we have some other guys that haven't really played much. I'm interested in seeing how Noke Tago plays during the spring because he looked good to me as a scout team player. We have some real possibilities there. Some of them are just unknown."

4. Building on the successful 2012 season: Last season was a banner campaign for Banker and the Beavers defense as they finished third or higher in the Pac-12 in five major statistical categories: total defense (354.0 yards per game), scoring defense (20.6 points per game), rushing defense (129.5 ypg), passing defense (224.5 ypg) and pass efficiency defense (112.6 rating). In addition, they stonewalled opponents on third down, holding them to a 29.3 conversion percentage (53-of-181), best in the Pac-12, and defended reasonably well in the red zone (82.9 scoring percentage).

Can Oregon State equal those numbers in 2013? Riley certainly thinks so, and eyes the Beavers making another jump this season towards becoming a consistently elite Pac-12 defense.

"Defensively, we want to expand on our ability to play well on third down," Riley said. "We started out the season really, really good there. Not that we weren't still pretty good at it, but weren't nearly as good towards the end as we were earlier. We want to maintain a high level of efficiency on third down and red zone defense. We also have a lot of individual development to do on defense."

5. New coaching dynamic: Last season, OSU has just three full-time defensive coaches, including Banker, who also coached the linebackers. However, shortly after last season ended, Riley bumped assistant head coach/tight ends coach Jay Locey into an administrative position and promoted Trent Bray to linebackers coach, balancing the staff with four on each side plus special teams coordinator Bruce Read.

While Bray enjoyed a prominent role last season, this will be the first time the four defensive coaches will work together. So, the dynamic among the coaching staff has changed. Riley, though, sees bright days ahead for the Beavers defense.

"I watched closely the dynamics of our defensive staff last year and really liked it," Riley said. "I think Trent added a lot to us defensively and he freed Coach Banker up to be the coordinator. He gave us a guy that even though young, gave us an experienced coach in our defense. He played for us and coached in a somewhat similar system when he was at Arizona State. He had coaching experience and playing experience with us. He fit very well into the dynamics of the defensive staff. It's a good picture to me. We've provided our team with the best possible scenario coming out of it."